Note: Descriptions are shown in the official language in which they were submitted.
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B09-89-009
DYNAMIC_ ELECTIVE CORRELAT N OF GRAPHIC ENTITIES
Related Documents
U.S. Patents 4,731,609 FAST CORRELATION OF MARKERS WITH
GRAPHIC ENTITIES and 4,754,267 FAST POINT/LINE CO~RELATIONS
IN GRAPHIC ENTITIES, assigned to a common assignee with this
application.
Background and SummarY o he Invention
This invention relates to selection of a displayed image
using a cursor and particularly to energizing a display
element to which the control by an input device is directed.
In CAD (Computer Aided Drafting -- or Design) graphic
applications, a cursor is used to select entities on a
display screen. The selected entity, e.g., a shape such as
a box or circle or line, is then highlighted to show the
user which entity has been selected. The user can move the
cursor about until the desired shape is highlighted by
changing color, intensity, blinking, or altering some other
attribute of the selected shape or entity.
Some CAD functions apply only to certain types of
entities. For example, when it is desired to modify text,
the text to be modified must be selected. Selection of
other entities, such as shapes, results in an error message
being displayed to the user that an improper entity has been
selected, requiring the user to reset the message and select
the correct entity, in this case text. The generation and
cancellation of the error message and subsequent selection
of another entity reduce the productivity of the user.
U.S. Patent 4,516,266 discloses graphics entity detection
independent from the image generation. Using a light pen to
select a pixel (picture element or dot making up the raster
display), the shape of which the pixel is part of can be
ascertained and highlighted. This is accomplished by
monitoring identifying signals provided with the data being
sent serially from storage to the display device. Such
identifying signals are associated with the features or
entities of which the data is a part.
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U.S. Patent 4,742,473 discloses a system for facilitating
interaction with a CAD system by allowing the user to select
one of a plurality of processing modes from a menu. The
input device i8 a digital tablet and the display has two
areas. Alphanumeric data is displayed on a status screen
and a cursor controlled by the digital tablet is monitored
by a computer which detects when the cursor moves between
the graphics work space and the menu region. In response to
such determination, the computer displays on the status
screen the modes available for selection when entering the
menu region and substitutes a mode-dependent status display
when the cursor enters the graphic work space.
Present systems select the correlated entity and highlight
it for verification before determining whether it is the
correct type of entity for the function being executed. As
noted above, this wastes time and requires the user to
perform extra operations to restart the selection process.
In accordance with the invention, a display image ia
selected e.g., using a cursor, for editing by an editing
operation that applies only to certain types of images. The
certain type of image is an operation attribute, i.e., t
specified as part of the operation. When the cursor selects
an image, its type attribute is checked. If it is the same
as the certain type specified by the operation, then the
image is highlighted for verification by the user. If it is
not the same, then the image is not highlighted and the user
must select another image or the system can select the next
nearest shape.
The invention eliminates the need for error messages by
associating the type of entity required by the function with
the entity correlated with the cursor. If not the same, then
the correlated entity is not highlighted and the user moves
the cursor until an entity is highlighted, ensuring that the
selected entity is the proper for the function. That is, if
text is to be modified, then only correlated text entities
will be selected and highlighted.
Another useful application of the invention is in GIS
applications (Geographic Information Systems). For example,
a public utility company user may want to connect power
distribution lines to insulators on poles. This would
require the user to select successive points on the display
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B09-89-009 3
with the cursor to indicate the sequence and place for the
wire t:o be connected. The invention can prevent the user
from inadvertently connecting the wire to trees~ houses,
signposts, and other points or objects that appear on the
display.
Brief Descri~tion of the Drawinq
The invention i8 described in detail by referring to the
various figures which illustrate specific embodiments of the
invention, and wherein like numerals refer to like elements.
FIG. 1 is a illustration of an application of the
invention.
FIG. 2 is a flowchart depicting the operation of the
invention.
FIG. 3 is an example of a type of database record useful
in implementing the invention.
Description of the Preferred Embodiment
The embodiment of the described invention can be in the
form of a subroutine. Subroutines are computer program
modules that are not placed directly in the stream of
instructions in which they are used. Subroutines are
invoked by call and link procedures which cause the program
execution to transfer to the list of computer instructions
comprising the subroutine program and to link or to supply
the operands used by the subroutine. When a subroutine has
completed execution, the program control returns to the
instruction in the calling program following that which
called the subroutine.
In the following description, references are made to the
flowcharts depicting the sequence of operations performed by
the program. The symbols used therein are standard
flowchart symbols accepted by the American National
Standards Institute and the International Standards
Organization. In the explanation, an operation may be
described as being performed by a particular block in the
flowchart. This is to be interpreted as meaning that the
operations referred to are performed by programming and
executing a se~uence of instructions that produces the
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result said to be performed by the described block. The
actual instructions used depend on the particular hardware
used to implement the invention. Different processors have
different instruction sets but the person of ordinary skill
in the art i~ familiar with the instruction set with which
he works and can implement the operations set forth in the
blocks of the flowchart.
Highlighting, as used in this specification, means to
cause a selected entity to stand out from the surrounding
entities on a display by changing its color, increasing or
decreasing its intensity, blinking, reverse video, or the
like.
In CAD applications, as well as in other computer graphics
applications, editing commands are provided to operate on
the graphic entities. For example, a TRIM function may be
supplied for cutting off a line crossing another line so
that the crossing line is terminated at the crossed line.
FIG. lA shows a crossed line 101 and a crossing line 103.
When the trim function is selected by the user, a prompt i8
displayed such as SELECT TARGET LINE. In response to the
prompt, the user can move a cursor to a desired target line,
in this example, the crossed line 101 which is highlighted
for verification. The user presses a button to select the
highlighted target, or crossed line 101.
The system then supplies a prompt SELECT LINE T0 BE
TRIMMED. In response, the user moves the cursor to the
crossing line 103 and, when it is highlighted, presses a
button to select it. (In the example, the part of the
crossing line on the side of the crossed line -- here the
right side -- selected by the cursor is trimmed.)
FIG. lB shows the displayed lines after the operation is
completed. The crossing line 103 terminates at the crossed
line 101.
If, however, as shown in FIG. lC, the text is selected in
response to the second prompt, the function cannot be
performed because text truncation is not allowed. When the
text is highlighted in response to the second prompt for
verification, and is selected by the user's button, the
system attempts truncation only to determine that the
selected ~hape was text. The system then supplies an error
message that the incorrect shape was selected.
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B09-89-009 5
The invention performs the sequence in a different order.
When the cursor is on or near the text shape as the shape to
be trirnmed, the shape type is checked before highlighting to
determ:ine whether it is an acceptable choice. If not, then
the text is not highlighted for verification and the user
must move the cursor until a proper response shape is
highlighted.
Feedback to the option code is not done automatically when
a correct entity is highlighted because the highlighted
entity may not be the correct entity although of the same
type. Feedback to the option is supplied only when the user
signals, e.g., by pressing a button, when the highlighted
entity is acceptable.
A flowchart of the embodiment of the invention is shown
in FIG. 2. A processing block 201 represents that an option
code, i.e., a command or function, is being executed. In a
processing block 203, a variable, SHPTYPE, is set to a shape
type or some identification corresponding to the type of
shape on which the option code operates. SHPTYPE can also
include several shape types when the option applies to more
than one type of shape.
An input/output block 205 prompts the user to select a
displayed shape. When the shape is selected by the user
generating a select signal, a subroutine block 207
represents that a subroutine is called. In the subroutine,
a process block 211 determines the X,Y coordinates of the
cursor. A process block 213 shows that the cursor location
is correlated to the closest shape to the location of the
cursor.
A decision block 215 determines whether this is a new
shape or whether it had been previously selected during the
subroutine. If it is not a new shape, the program returns
to the process block 211 to check the next closest shape.
If it is a new shape, the attributes of the selected shape
are determined, such as by accessing a database record, as
represented by a process block 217.
A decision block 218 determines whether the type of the
selected shape is the same as the SHPTYPE variable. If not,
the program moves to the output block 216 to cause another
shape to be selected. Otherwise, the selected shape is
highlighted as shown in process block 219 and the subroutine
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B09-89-009 6
program returns to the option code as indicated by the
process block 209. The decision block 218 may compare the
attribute shape to several shape types included in SHPTYPE
when the latter applies to more than one type of shape.
The above-described process is repeated after the user has
been prompted to select another shape or when the next
closest shape is selected.
A preferred implementation of the processes shown in the
process blocks 211 and 213 are described in detail in U.S.
patents 4,731,609 and 4,754,267.
A typical record entry for a database associated with the
system being described is shown in FIG. 3. The first field
is a shape number 301 which correlated to a selected display
shape number. Next, a command list 303 is stored which can
possibly contain several operations such as plot. Next, a
vector list 305 is supplied which indicates the X,Y
locations of lines and other data re~uired to plot the
shape. An attribute list 307 contains information as to the
color of the shape, the shape type, whether the shape is
filled, and so on.
When a shape is to be highlighted by changing the color,
the color attribute of the attribute list 307 is changed and
the shape is redrawn.
Similarly, by accessing such a record, the shape type can
be retrieved from the attribute list 307.
While the invention has been particularly shown and
described with reference to a preferred embodiment thereof,
it will be understood by those skilled in the art that
various changes and modifications in form and details may be
made therein without departing from the spirit and scope of
the invention according to the following claims.
